<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>box model</title>
    <style>
        .box {
            background-color: gray;
            width: 300px;
            height: 300px;
            /*padding: 10px;  !*四个方向，内边距全为10px*!*/
            /*padding: 10px 20px;  !*上下内边距为10px，左右为20px*!*/
            /*padding: 10px 20px 30px 40px;  !*方向为上右下左*!*/
            padding-top: 10px;
            padding-right: 20px;
            padding-bottom: 30px;
            padding-left: 40px;
            border-left: 5px dashed darkgreen;
            border-right: 5px dotted darkorange;
            border-bottom: 5px solid purple;
            /*margin: 30px;*/
            margin: 10px auto;
        }
    </style>
</head>
<body>
<div class="box">
    Hello World!
</div>
</body>
</html>